Abstract: Based on energy conservation and transformation caused by the interaction of caving rock and air in the course of roof caving in large-size mined-out area,a wind speed model of impact waves was constructed and an experimental device was designed.Experimental results show that with the increasing of rock falling height,the amplitude of wind speed of impact waves slowly increases.The small-size inflator model in a large cross-section space could better describe air flow during roof caving,but air shock waves should be expressed by the inflator and external flow compound model.The established experimental and theoretical models have a great similarity.